The manufacturing community utilizes air cylinders and other air actuated devices to control machinery, operate tools, and to perform various other manufacturing activities. These devices may be air actuated in a single direction with the return being accomplished by springs and/or gravity, or these devices may be air actuated in both directions with the control of the device being accomplished with an air valve. At certain times, the need arises to disconnect the supply of compressed air to the device. For example, one such time occurs when service or maintenance is required on the system incorporating air actuated devices. When disconnection of the supply of compressed air is required, normal precautions dictate that the disconnect valve must be locked to prevent reactivation of any valves, tools or associated machinery in the system while the system is being maintained and/or repaired. In the case of a system incorporating air operated equipment, a lockout valve should be used to cut off the compressed air supply to the system and to exhaust any stored or residual downstream air.
However, during the exhaust process, it is often important for the operator to verify that air pressure has in fact been exhausted from the output end of the lock out valve. Unfortunately, in conventional lockout valves, the pressure at the output is not readily measurable by the user, and hence the operator is unable to confirm that the exhaust process was completed to a safe pressure level. Therefore, in the interest of caution, it is preferable to confirm that pressure has been reduced to a safe level prior to service and/or repair.
Accordingly, there exists a need in the relevant art to provide a means to determine the outlet pressure of a fluid control valve to determine when a predetermined pressure is achieved. Additionally, there exists a need in the relevant art to incorporate a pressure indicator in a fluid control valve to improve the safety features thereof by providing a simple method of determining when air pressure has been reduced at the output or conversely reestablished.